| The brain is the core organ of the human being,which governs all human life activities.Neurons are the basic units of the brain,the neuron connection network formed by different neurons in a specific way crucial for the realization of brain function.Studies have shown that the pathogenesis of some diseases is closely related to the formation and regulation of the neural network.Therefore,obtaining the whole-brain neural network is important for the brain diseases and brain research.Agarose embedding is a common method in neuroimaging,the sample is embedded in agarose,without damage to the morphology,fluorescence signal and antigenicity.However,due to the performance of the slicing device and the difference in the internal structure of the mouse brain,the cutting quality is poor.The focal plane should be placed at a deeper position below the surface of the sample to reduce the influence on the imaging quality,the signal will be uneven,so the application of this embedding method is limited.Therefore,this paper studied the vibration cutting method applied for the agarose-embedded mouse whole brain,with the purpose of improving the cutting quality and obtaining the whole brain neural connection networks.In order to solve this problem,this paper proposes a specific approach for the study of mouse whole brain vibrating cutting method.By analyzing the soft tissue cutting process,the important factors affecting the cutting quality are determined.The design requirements of the vibratome for whole brain cutting research are proposed combining with existing devices.Through using the designed vibratome to study the cutting performance of the whole brain,the quantitative relationship between the cutting quality and cutting parameters are established.The optimal parameters for different positions in the whole brain are selected in the end.This paper designs a vibratome based on flexible mechanism,which includes four parts: voice coil motor drive module,transmission mechanism,vibration structure and blade adjustment mechanism.The voice coil motor drive module is designed to achieve the continuous adjustment of amplitude and frequency.The use of the transmission mechanism with high stiffiness in the Y and X directions,the accuracy of the driving force transmission was realized and the error caused by the installation of the voice coil motor is effectively controlled.The design of the vibration structure based on the double parallelogram enabled linear motion trajectory,and the Z-direction error is reduced.Designing the blade adjustment mechanism to achieving the precise adjustment of the blade roll angle in the range of 0~3.9°,which is convenient for adjusting the blade installation direction and the vibration direction to be approximately parallel and reducing the Z-direction error.Through the performance test of the device,it is verified that the designed system can continuously adjust the frequency and amplitude within 0~100 Hz and 0~0.5 mm,and can strictly control straightness error within 2.5 ?m and the Z-direction error within 3 ?m.The mouse whole brain vibrating cutting method is studied using the designed vibratome.The effects of vibrating cutting parameters on the cutting quality of different positions of mouse brain is studied.The real-time staining of PI combined with optical imaging method is used to accurately recover the profile of the cross-section,and the quantitative relationship between cutting quality and cutting parameters is determined.By optimizing the cutting parameters,the surface roughness of mouse brain can be effectively controlled within 20 ?m.Finally,the wear analysis of the ceramic blade used in vibratome is carried out,The experiment prove that after cutting four intact mouse brain samples with 8 ?m slice thickness,the edge wear defects don't exceed 5 ?m. |
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